Process for the manufacture of manganese steels



Patented Mar. 31, 1925.

UNITED s'rATEs PATENT oer- FQURNEAUX, roaens er AGIEBIES DE roMrEY, cereals, FRANCE.

, PROCESS FOR THE MANUFACTURE OF MANGANESE STEELS.

No Drawing.

To all whom it may concern:

Be it known that I, MAURICE FoULn, citizen of the French Republic, residing at Paris, in the French Republic, have in vented new and useful Improvements in Processes for the Manufacture of Manganese Steels, of which the following is a specification.

The present invention has for its object a process for the manufacture in the basic or neutral converter of hard steels containing a large proportion of manganese, such as Hadfield steels for example, by the blow ing in said converter of rich spiegels.

In a cast iron treated upon a basic lining, the proportion of manganese, after having undergone a great reduction during the period of burning of the silicon, decreases only much more slowly during the decarburation. This is in accordance with the principle stating that carbon, beyond a certain minimum temperature, has a greater afiinity for oxygen than any other element. The manganese thus burns in rather great quantity only during the relatively cold period termed sparking period, that is to say before the ignition of the flame of the carbon. As soon as the heating of the whole mass is sufficient to provide for the starting of the decarburation, this lat ter reaction takes precedence over all the other oxidations which become then only of a minor importance.

With these remarks in view, I had the idea of treating in the basic converter a nonphosphoric cast iron, which, at first sight, would seem unreasonable, but which ensures a very important practical result, as is further set forth, if care is taken to choose as the nonphosphoric cast iron, a high manganese cast iron, containing for example 15 to 20 per cent of manganese, such as high manganese spiegel which always contains the necessary proportion ofsilicon to ensure the operation which will he fur ther described.

The method of operating is as follows: One brings the liquid spiegel from the blast furnace or any other source (cupola furnace, melting furnace, etc.) into a basic or neutral converter preliminarily heated by preceding operations. The addition of lime is very small or even nil, the slag being made sufliciently basic by the combustion of Application filed July 10, 192 seri llilo- 650,733.

ature.

The operation starts with the combustion of of a part of the manganese, andas'soon as the temperature is sufficient, the carboncommences to burn; at this time but little silicon remains, but there still remains the major part of the manganese whose elimination will now take place very slowly whereas on the contrary the carbon is rapidly eliminated. The carburation is examined with the spectroscope by the usual methods, and the operation is stopped when the proportion of carbon is that desired. i

The metal obtained still containsa large proportion of manganese, for example 10 to 12 percent as for the Hadfield steel whose uses are well known. One can thus, when starting with a suitable cast iron treated by this process, obtain in fact a steel having ICE MAURICE room), or PARIS, FRANCE, assrenon TO SOCIETE ANONYME bEsfnAo'rs -mass of lime fed into the furnace at the lower outer temperthe silicon and then by the' combustion Working of the dea predetermined proportion of carbon and in the Martin furnace or in an electric furnace, either to change the relative proportionsof carbon and manganese within wide limits, or to add new elements, metals or metalloids of aspecial nature.

It should be observed that with the general process above described, the quantity of manganesewhich is oxidized during the starting and which is contained in the slag is not lost; it may be recovered by treating this slag in the blast furnace.

aving now described my invention, I declare that whatI claim as new and desire to secure by Letters Patent is:

The process for manufacturing high man ganese steels which consists in charging into a basic converter a bath of non-p hosphoric I through manganese than in the steels to manufacture and less than 5% of carbon and 1% of silicon, in blowing an oxidizing agent said bath to burn the silicon and a small part of manganese hereby elevat ing the temperature of the bathto a determined point above Which the oxidation of the carbon supplants that of the manganese, and in continuing to blow said oxidizing agent through the bath hereby decarburizing the latter.

in testimony whereof I have signed my name to this specification.

MAURICE FOULD. 

